diff --git a/Meter.c b/Meter.c
index 56a6025e72eef6e752392c9efb89132873a54459..52dbdd9ddb3495e808a117d40765675f4650b397 100644
--- a/Meter.c
+++ b/Meter.c
@@ -152,7 +152,7 @@ int Meter_humanUnit(char* buffer, unsigned long int value, int size) {
       if (value / 1024 < powi)
          break;
 
-      if (prefix[1] == 0)
+      if (prefix[1] == '\0')
          break;
 
       powi *= 1024;